Pioneering Security: Uniting Team Synergy with Commercial and Technical Expertise

In today's interconnected world, the telecommunications (telco) industry is a prime target for various cyber-attacks, making robust security measures essential. Johannes Opitz, Ph. D. and Natalia Doulenkova discuss the synergies between commercial and technical roaming, and steps they are taking together to enhance the telco landscape.

Natalia: Johannes, we have an interesting topic to share with the audience today – what are we doing at Deutsche Telekom to make the telco ecosystem better and safer? You are responsible for all commercial roaming of Deutsche Telekom globally, covering centralized roaming strategy and dealing with all our roaming partners worldwide. Additionally, you are one of the drivers of our Group Compliance with the GSMA Global Title (GT) Lease Code of Conduct (CoC). Can you explain why this topic is so important to you? 

Johannes: As someone working in security, you know well how dangerous GT abuse can be, serving as a gateway to financial fraud, data theft, user tracking and many other fraud cases. Nevertheless, leased GTs are widely used, and the only policy regulating this usage and limiting their abuse is the GSMA GT Lease CoC. I believe that our compliance with this CoC not only protects our subscribers and partners, but also sets an example for other operators and providers. Can you share with the audience what actions you have taken on the DT provider side to support this initiative?

Natalia: Sure – with pleasure. To support our compliance and to go beyond classical firewalling, we've restricted access to our signaling network to mobile operators only, aiming to combat fraud coming from messaging, often via GTs leased by SMS-aggregators.

Johannes: But there are always operators still accepting messaging over SS7 signalling collected by aggregators, how do you handle that?

Natalia: That’s possible only thanks to the close cooperation with our customers. We whitelist GTs provided by them, as we know they are dedicated for legitimate SMS traffic, and we block the rest. But we have one more topic in common in this respect, right?

Johannes: True – you are talking about Machine-to-Machine (M2M) traffic, and I’m glad that we have found the right balance on that as well. It’s not a secret that M2M players are often MVNO’s, meaning that they don’t have their own GTs. This brings us back to the topic we started with today. Representing a Group of mobile operators, I can’t ignore M2M traffic – though, I need to ensure that it’s a traffic we are happy to carry on all our networks. Our collaboration in the field of M2M is another step to make the telco ecosystem better.

Natalia: Yes, we carefully assess each M2M case. Some of them require not only Diameter and GRX, but also Signalling (for older devices, specific use-cases in automotive, or due to breakdowns). We are very cautious before opening our networks to new unknown players, seeking consent from operators, and requiring written guarantees from M2M MVNOs about adhering and following the GSMA CoC on GT leasing.

Johannes: Now, more collaboration is needed globally among providers and operators.

Natalia: Indeed. Thank you, Johannes, it’s a pleasure working with you.